Made ganetiviz views pep8 compliant, removed redundant imports.

refs #15009
Made ganetiviz urls pep8 compliant.

refs #15009
Updated ganetiviz urls to correct model imports as per new gwm layout
ganetiviz/urls.py - Relaxed the instance_hostname matching regex in to match any string
(except forward slashes)
Deleted the redundant views in ganetiviz
Removed some rendudant lines in ganetiviz views.
Remove unnecessary line.
Fix dict comprehension for python 2.6